Factsheets Drinking Water饮用水处理方法及指标

Pressure filtration
closed filters where the driving force during fitration is the difference in water pressure above and below the filterbed; this pressure difference can be dramatically increased to 5-15 m water column; with this, despite a fast clogging of the filterbed, long run times can be achieved
(BIO)FILTRATION
oxidation of CH4
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Factsheet 2.1. Technologies for drinking water production from groundwater (continued). Open and closed filters in which the top of the filterbed remains "dry"i.e. lacks the water layer; because of the absence of water, there is always air in the filterbed and the used oxygen can be replenished
Treatment for removal of
methane, iron, manganese, ammonium, calcium
humic substances, particles (e.g. algae), pesticides, organic micropollutants, pathogens
(2): 4e- + O2 +2H2O → 4OH(3): 8H2O → 8OH- + 8H+ (4 overall): 4Fe2+ + O2 + 10H2O → 4Fe(OH)3(s) + 8H+ Biological: methane which was not removed during aeration is "burned"by methaneoxidizing bacteria (methanotrophs) in the filter: (1): CH4 + 2H2O → CO2 + 8H+ + 8e(2): 8e- + 2O2 +4H2O → 8OH(overall): CH4 + 2O2 → CO2 + 2H2O
Factsheet 1. 2. General flowchart of drinking water supply system.
ABSTRACTION
TREATMENT
STORAGE & TRANSPORTATION
DISTRIBUTION NETWORK
Water Technologies in the Global Context 2016
AERATION
input of O2, removal of CO2, CH4, H2S
Physical: aeration/absorption (gas to water), gas transfer/desorption(gas from water)
Water is brought in contact with air to change the content of dissolved gases in water.
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Factsheet 1. 1. Drinking water sources.
Source
Groundwater (deep anaerobic)
Surface water
Anthropogenic influence
In general well protected by impermeable soil layers Under direct influence of human activities. No physical (clay), anthropogenic influence (pollution) is limited protection: anthropogenic influence (pollution) is high
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Contents
Drinking Water Sources Factsheet 1. 1. Drinking water sources. ......................................................................................................................................................................... 4 Factsheet 1. 2. General flowchart of drinking water supply system. ............................................................................................................................ 4 Groundwater Treatment Factsheet 2. 1. Technologies for drinking water production from groundwater. ......................................................................................................... 6 Factsheet 2. 2. Stages in the treatment of groundwater............................................................................................................................................. 10 Surface Water Treatment Factsheet 3. 1. Technologies for drinking water production from surface water. ...................................................................................................... 12 Factsheet 3. 2. Application field for conventional and membrane filtration. ............................................................................................................. 18 Factsheet 3. 3. Common drinking water treatment schemes. .................................................................................................................................... 19 Sludge and backwash water treatment Factsheet 4. 1. Treatment of backwash water and sludge from drinking water production. ..................................................................................... 21
Goal
Processes involved
Principle
Spraying
Applied techniques
water is dropped through the air in fine droplets water is divided into thin layers small air bubles are blown through the water open filters in which water flows from the top to the bottom through the filterbed; a water layer is present on top of the filterbed
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Drinking Water Sources
Water Technologies in the Global Context 2016
Factsheets Drinking Water
Cascades/waterfall aeration Bubble aeration
Chemical oxidation of ferrous iron (1), followed by hydrolysis (2,3). As a result flocs of iron hydroxide are formed (4). These are filtered in the filterbed (physical). oxidation and hydrolysis of Fe3+ (1): 4Fe2+ → 4Fe3+ + 4e-
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Groundwater Treatment
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Factsheet 2. 1. Technologies for drinking water production from groundwater.
Rapid Sand Filtration (RSF) Water flows from top to the bottom through a filterbed, usually sand with a more or less uniform diameter. The filterbed acts more like a "reactor" than a filter, by providing a contact surface onto which bacteria and reaction products can adhere. Compounds dissolved in groundwater are oxidized in various chemical and biological processes. Because of differences in reaction kinetics, various zones, where a certain process dominates, can be determined in the filter. The reaction products which accumulate in the filterbed needs to be removed (almost) daily by backwashing the filter with an upward water flow.